Flame resistant polyurethane prepared by adding an ethane diphosphonate into the urethane-forming mixture

ABSTRACT

Fire resistant polyurethane compositions are prepared by adding to the urethane-forming reaction mixture a substituted ethane diphosphonate having the formula   WHEREIN R1 and R2 are hereinafter defined, R3 is hydrogen or an organic radical, and n is an integer having a value of 1 or 2.

United States Patent Kerst 5] May 23, 1972 FLAME RESISTANT POLYURETHANE3,525,708 8/1970 Clark et al. ..260/77.5 PREPARED BY ADDING AN ETHANE3,544,509 12/1970 Carroll et a] ..260/2.5

DIPHOSPHONATE INTO THE URETHANE-FORMING MIXTURE lnventor: Al F. Kerst,Littleton, Colo.

Assignee: Monsanto Company, St. Louis, Mo.

Filed: Apr. 13, 1970 Appl. No.: 27,985

US. Cl ..260/2.5 AJ, lO6/l 63, 260/18 PN, 260/22 R, 260/45.7 P, 260/75NR, 260/77.5 AR, 260/502.4 P, 260/862, 260/932 Int. Cl ..C08g 22/ 16Field of Search ..260/2.5 A], 77.5 AR, 75 NR, 260/932 References CitedUNITED STATES PATENTS 7/1969 Jacques et al ..260/77.5 6/1963 Friedman...260/77.5 5/1968 Birum et al. ..260/77.5

Primary Examiner-Donald E. Czaja Assistant ExaminerEugene C. RzucidloAtlarneyl-lerbert B. Roberts, Roger R. Jones, James J. Mullen and NealE. Willis [57] ABSTRACT Fire resistant polyurethane compositions areprepared by adding to the urethane-forming reaction mixture asubstituted ethane diphosphonate having the formula 4 Claims, NoDrawings FLAME RESISTANT POLYURETHANE PREPARED BY ADDING AN ETHANEDIPI'IOSPHONATE INTO THE URETI'IANE-FORMING MIXTURE ORGANIC COMPOSITIONSThis invention relates to organic polymeric compositions and, moreparticularly, provides novel polymeric compositions having increasedresistance to burning and a method for rendering polymeric compositionsflame retardant.

It is an object of this invention to provide new and useful polymericcompositions.

It is another object of this invention to provide methods for increasingthe resistance of organic polymeric compositions to the action of flamesand for making them more resistant to burning action in general.

An additional object of this invention is to provide in polymercompositions an organic phosphorus compound having reduced tendency todecompose and/or degrade from the polymer compositions when the polymersystem is subjected to elevated temperatures,

Other objects, advantages, and aspects of this invention will becomeapparent from a reading of the specification and the appended claims.

This invention provides, as new compositions of matter, an organicsynthetic polymer (linear or cross-linked) in combination with asubstituted ethane diphosphonate as defined herein.

Another aspect of this invention provides, as new compositions ofmatter, synthetic copolymeric materials prepared using as a comonomer asubstituted ethane diphosphonate as defined herein.

A still further aspect of this invention provides a method for reducingthe tendency of organic synthetic polymers to burn after a source ofburning heat has been removed from the polymeric composition byincorporating into the organic synthetic polymeric compositions asubstituted ethane diphosphonate as defined herein.

Other objects will become apparent from a reading of the followingdescription.

It has been found that certain organo-phosphorus compounds, i.e.,substituted ethane diphosphonic acids and their esters, can be added to,blended with, or co-polymerized with the synthetic polymeric materialsto accomplish the aforegoing objectives.

These substituted ethane diphosphonic acids and their esters have thefollowing generic formula:

(I) o H In the above formula I, R can be from the group oxygen; halogen;hydroxy; CN; N(R,) where R is from the group hydrogen and alkylcontaining from one to 30 carbon atoms, preferably from one to eightcarbon atoms, and more preferably from one to four carbon atoms; XRwhere X is from the group oxygen and sulfur and R is from the groupalkyl containing from one to 30 carbon atoms, preferably one to eightcarbon atoms, more preferably one to four carbon atoms; C 11 (phenyl)and CH -C l-I,, (benzyl); acetoxy; 50 R where R is the same as definedabove; benzoyl; CO H; and CH(COOR where R, is an alkyl group containingfrom one to 30 carbon atoms, preferably from one to eight carbon atoms,and more preferably from one to four carbon atoms.

In the aforegoing general formula I, R is from the group R exceptoxygen, and hydrogen. It is to be understood that R then is never oxygenand R is only hydrogen when R is oxygen. Additionally, it is to beunderstood that in all cases, ex-

cept when R, is oxygen and R is hydrogen, at least R, or R is a hydroxygroup. In other words and for exemplary purposes only, when R ischlorine, R must be a hydroxy group.

In conjunction with the proviso that R is only hydrogen when R is oxygenwith reference to the aforegoing general formula I, n is an integerhaving a value of l or 2 and n is only 1 when R is oxygen.

In formula I, R, is from the group hydrogen, alkyl, alkenyl, aryl, alkylaryl, cyclic and alicyclic.

In conjunction with the foregoing general formula I and morespecifically when the ethane diphosphonate is in the ester form thereof,i.e., R is an organic radical heretofore mentioned, the preferredsubstituents are the following:

a. alkyl containing from about one to about 18 carbon atoms (morepreferably one to four carbon atoms);

b. alkenyl containing from about one to about 18 carbon atoms;

c. aryl phenyl, naphthyl, anthryl, or phenanthryl;

d. alkyl aryl hydroxy, halogen, lower alkyl, (alkaryl) having from oneto about six carbon atoms, and amino substituted phenyl, naphthyl,anthryl, or phenanthryl;

e. cyclic containing from about four to about eight carbon atoms andthere may be present in the ring either a nitrogen, sulfur, oxygen orphosphorus atom; and

f. alicyclic containing from about four to about 10 carbon atoms. It isto be understood that all of the compounds falling within the aboveformula I and as heretofore defined are generically described herein asethane diphosphonates." In other words then, the acids, esters andmixtures thereof are all generically described herein as ethanediphosphonates.

In general, the ethane diphosphonates are prepared by contacting anepoxy ethane diphosphonate having the following formula:

wherein R is the same as defined above, with a de-oxiranization agentwhich opens the ring of said epoxy compound (and provides thesubstituents on the carbon atoms) to form the ethane diphosphonatesfalling within formula I. It is to be understood that the term epoxyethane diphosphonate" used herein generically describes and encompassesthe acid and ester forms, and said term is designated at times hereinEEDP for the sake of brevity.

The de-oxiranization agents which effect this ring opening" are from thegroup water, ammonia, primary amines, secondary amines, acids,malonates, alcohols, mercaptans, Lewis acid catalysts and mixturesthereof. The specific application of these de-oxiranization agents aredisclosed in the processes which are described hereinafter.

In conjunction with the water agent, this ring opening of EEDP iseffected by hydrolysis at a temperature of from about 50 C. to about C.with or without an inert diluent and acid catalyst, e.g. (respectively),dioxane and HCl.

As illustrative of the ethane diphosphonates which can be preparedaccording to the aforementioned hydrolysis reaction of EEDP, there maybe mentioned, without limitation, the following compounds:

1,2 dihydroxy ethane-1,1-diphosphonic acid tetraethyl 1,2 dihydroxyethane-1,1-diphosphonate diphenyl 1,2 dihydroxy ethane-1,1-diphosphonatedibutyl 1,2 dihydroxy ethane-l,l-diphosphonate The de-oxiranizationagents ammonia, primary amines and secondary amines are genericallyequated (RJ NH and R has the same connotation hereinbefore ascribed.This ammonolysis reaction of (R ,NH with EEDP is generally conducted ata temperature between about 40 C. and about 150 C. under atmosphericconditions.

As illustrative of the ethane diphosphonates which can be preparedaccording to the aforementioned ammonolysis of EEDP, there may bementioned, without limitation, the following compounds:

Z-aminol hydroxyethanel l diphosphonic acid Z-hydroxy-l-aminoethane-ll-diphosphonic acid tetraethyl Z-amino-l-hydroxyethanel l-diphosphonateZ-methylaminol-hydroxyethanel l diphosphonic acid Z-diethylaminolhydroxyethanel l diphosphonic acid dibutyl 2-dibutylaminolhydroxyethanel ldiphosphonate The acid" de-oxiranization agents,designated herein as HZ, relate to certain inorganic and organic acidswhich effect the ring opening. Specifically, the cation, Z, is from thegroup halogen (such as chlorine, bromine, fluorine and the like), CN,acetoxy (CH COO), sulfonate (80 R, wherein R has the same connotation asheretofore set forth and is from the group hydrogen and alkyl), benzoyl(C H CO), and carboxy (HOOC). This acid reaction is generally conductedat a temperature between about C. and 150 C. under atmosphericconditions.

As illustrative of the ethane diphosphonates which can be preparedaccording to the aforementioned acid reaction with EEDP, there may bementioned, without limitation, the following compounds:

2-chlorol hydroxyethane-l l diphosphonic acid 2-hydroxyl chloroethane-ll diphosphonic acid tetraethyl Z-cyanol hydroxyethanel l diphosphonateethyl Z-sulfol hydroxyethane-i l diphosphonate diphenyl 2-lluorolhydroxyethanel l diphosphonate 2-ethylsulfol-hydroxyethanel ,1diphosphonic acid The malonate de-oxiranization agent referred to hereinas MHC(COOR wherein R is the same as hereinbefore ascribed and M is analkali metal such as sodium, can be reacted with EEDP at a temperaturebetween about 5 and about 240 C. under atmosphere conditions to formsaid ethane diphosphonates.

As illustrative of the ethane diphosphonates which can be preparedaccording to the aforementioned malonate reaction with EEDP, there maybe mentioned, without limitation, the following compounds:

diethyl (2-hydroxy-2,2-diphosphonoethyl) malonate diethyl (2-hydroxy-l ldiphosphonoethyl) malonate dibutyl (2-hydroxy-2,2-diphosphonoethyl)malonate dimethyl (tetraethyl 2-hydroxy-2,2-diphosphonoethyl) malonatedimethyl (2hydroxy-2,Z-diphosphonoethyl) malonic acid The alcohol andmercaptan de-oxiranization agents, generi' cally referred to herein as RXH, wherein R is the same as hereinbefore ascribed and X is oxygen orsulfur, can be reacted with EEDP at a temperature between 5 C. and 180C. under atmospheric conditions to form said ethane diphosphonates. Thealcohols utilized are the monoatomic aliphatic alcohols containing fromone to 30 carbon atoms, preferably from one to eight carbon atoms,including the respective isomers thereof. Typical alcohols include, forexample, methanol, ethanol, propanol and n-butyl alcohol, It is alsowithin the scope of these processes to utilize alcohols such as phenoland benzyl alcohol. The mercaptans utilized are the aliphatic mercaptanscontaining from one to about 30 carbon atoms, preferably from one toeight carbon atoms, and include, for exemplary purposes only, methylmercaptan, ethyl mercaptan, propyl mercaptan and n-butyl mercaptan. Theisomers of the various mercaptans are also included herein.

As illustrative of the ethane diphosphonates which can be preparedaccording to the aforementioned reaction of EEDP with either alcohols ormercaptans, there may be mentioned, without limitation, the followingcompounds:

2-methoxy- 1 hydroxy ethane-l 1 diphosphonic acid Z-hydroxy- 1 methoxyethane-l l diphosphonic acid tetraethyl 2-ethoxy-l hydroxyethane-1,1-diphosphonate Z-thiomethyl- 1 hydroxy ethane-l l diphosphonicacid 2-phenoxyl-hydroxy ethane-1,1-diphosphonic acid 2-thiophenyl,l-hydroxy ethane-1,1-diphosphonic acid The reaction of EEDP in thepresence of a metal halide Lewis acid yields the oxy derivativeaccording to the following equation:

[ Lewis acid H CC[P 030 :0212

In conjunction with the above reaction, a wide variety of Lewis acidscan be utilized in order to effect an acid catalyzed rearrangement ofthe epoxy ethane diphosphonate. There may be mentioned for exemplarypurposes only and without any limitation metal halide Lewis acids suchas boron trifluoride, zinc chloride, magnesium bromide, ferric chloride,stannic chloride, titanium chloride, zirconium chloride, aluminumchloride and the like. in conjunction with the utilization of the Lewisacid for the acid catalyzed rearrangement, it is preferred to firstdissolve or suspend the metal halide in a nonaqueous inert aproticsolvent such as nitromethane, dichloromethane, nitrobenzene,nitropropane, chlorobenzene, dichlorobenzene, dichloroethane,tetrachloroethane, perchloroethylene, petroleum ether, carbontetrachloride, chloroform, carbon disulfide, ethyl ether, benzene andthe like, and then contact the resultant solution or slurry with theEEDP material. The amount of solvent utilized is not a limiting factoras long as that amount chosen does not substantially adversely affectthe preparation of the desired end product.

The acid catalyzed rearrangement of the epoxy ethane diphosphonate isgenerally conducted with the epoxy ethane dipphosphonate and a Lewisacid catalyst (and, if desired, an inert aprotic solvent such as ethylether) at a temperature between about 20 C. and C., and underatmospheric conditions. Higher or lower temperatures can be utilized,e.g., as low as 50 C. and as high as 250 C., depending, for example,upon the boiling point of said solvent. It is within the scope of thepresent invention that super-atmospheric (e.g., from about 1 to 10atmospheres) and sub-atmospheric (e.g. to 760 mm Hg) conditions and alsoin an inert atmosphere such as nitrogen or helium may be utilized whereone so desires.

The quantity of Lewis acid catalyst utilized in conjunction with theacid catalyzed rearrangement will vary somewhat, depending upon the typeof metal halide Lewis acid catalyst utilized, the temperature at whichthe reaction takes place, and, in some instances, the pressure of thesystem. It is to be understood that any amount of Lewis acid catalystcan be utilized as long as that amount is not substantially detrimentalto achieving the desired end product. It is found that from about 0.01to about 4 mole equivalents of said catalyst for each mole of EEDPstarting material suffices to form the aforesaid oxy," derivative insatisfactory yields.

As illustrative of the ethane diphosphonates which can be preparedaccording to the aforementioned acid catalyzed rearrangement of EEDP,there may be mentioned, without limitation, the following compounds:

2-oxy ethanel ,l-diphosphonic acid tetraethyl 2-oxyethane-1,1-diphosphonate dibutyl 2-oxy ethane-1,1-diphosphonate Theaforementioned epoxy ethane diphosphonates (EEDP) which are the basicstarting materials in conjunction with the preparation of the ethanediphosphonates falling within formula I can be prepared, for example, byreacting the disodium salt of ethylene diphosphonic acid, i.e.,

with hydrogen peroxide (which functions as an epoxidizing agent) in thepresence of a catalyst such as sodium tungstate. The above ethylenediphosphonate, also sometimes referred to in the art as vinylidenediphosphonate, is known in the art (in its ester form and processes forpreparing the same) as exemplified by US. Pat. No. 3,062,792, which isincorporated herein by reference. The ethylene diphosphonic acids andsalts per se and processes for preparing the same as described inCanadian Pat. No. 81 1,736, which is incorporated herein by reference.

The presently provided ethane diphosphonates are useful as modifiers aswell as flame retardants for synthetic polymeric materials. These ethanediphosphonates may be used in a quantity which is equal to that of thepolymer, but in most instances favorable results with respect toimprovement in flame-retardance are obtained at concentrations which aredefinitely lower. In some cases amounts as little as 0.1 percent, byweight of polymer and ethane diphosphonate, may be used, althoughgenerally it is preferred that amounts of from about 1 percent to 50percent be used to provide polymeric systems with reduced burning rates.Use of the present ethane diphosphonate with the polymeric materials inquantities which confer beneficial properties to the polymers withrespect to a desired effect, i.e., flame retardance, often confers tothe polymer an improvement also in such characteristics as resistance toimpact, dimensional stability, moldability, dye receptivity and thelike. Hence in order to arrive at optimum beneficial effect suited tothe purposes for which the polymeric composition is designed, onlyroutine testing, involving variation of adjuvant quantity is generallyrequired, although in some instances one or more members of the wholeclass of the presently provided ethane diphosphonate will be found toimpart a degree of modification at a low concentration which can beattained by other members of the class at significantly higherconcentrations.

The flammability test for measuring the burn qualities of polymersamples is for the most part essentially the standard burn test known asASTM-Dl692-59T (which is incorporated herein by reference) ormodifications thereof. As used herein a polymeric composition isconsidered nonburning if there is no evidence of burning (flame orprogressive glow) after removal of the burner and a self-extinguishing"sample is one that continues to burn after removal of the burner but theflame goes out before the second gauge line is reached.

In general, the ethane diphosphonates can be used as a comonomer inplace of or in combination with conventionally used dibasic or polybasiccarboxylic anhydrides, such as phthalic and maleic anhydride, to formsynthetic polymeric systems. The ethane diphosphonates, for example, canundergo reactions with reactive hydrogen-containing materials whichinclude polyamines containing at least two amine groups with a reactivehydrogen on each group and polyhydroxyl-containing organic compounds(containing at least two hydroxyl groups with a reactive hydrogen oneach group) including polyhydric alcohols, phenols and the like. Adistinct advantage of the present invention, therefore, is theflexibility which the ethane diphosphonates exhibit in formulating andpreparing polymeric compositions. For example, they can be used withpreformed monomers, copolymers and the like or they can be used as acomonomer to form polymers with other appropriate monomer materials.

In general, the polyhydric alcohols which are useful in preparingpolymers by reaction with the ethane diphosphonates include glycerol,pentaerythritol (including diand tripentaerythritol), sorbitol,mannitol, and the glycols (including the alkyleneglycols and thepolyalkylene glycols in which the alkylene group is (CI-I wherein n isan integer from 2 to 10), such as, ethylene glycol, propylene glycol,butylene glycol, diethylene glycol, dipropylene glycol, triethyleneglycol, tetraethylene glycol, hexamethylene glycol, decamethylene glycoland the like.

In general, the polyamines which are useful in preparing polymers byreaction with the ethane diphosphonates include the alkylene polyamines(particularly the alkylene diamine, triamine, and tetraamines in whichthe alkylene group is CI-I wherein n is an integer from 2 to 10) suchas, ethylene diamine, diethylene diamine, hexamethylene diamine,decamethylene diamine, triethylene tetraamine, pentamethylene triamine,hexamethylene tetraamine, butylene diamine, and the like.

Usually, all that is necessary is to mix the ethane diphosphonates andpolyamine and/or polyhydric organic compounds, preferably in amounts ofabout one functional substituent containing carbyl group, eg

per amine or hydroxyl group, although amounts on said carbyl group toamine or hydroxyl group ratio of from about 1:10 to 10:1 can be used,and heat to elevated temperatures, such as from about 40 C. to themelting point of the reactants (under atmospheric pressure, althoughsub-atmospheric pressures as well as pressures in excess of atmosphericcan be used) with temperatures above about C. being preferred. Inaddition, it is sometimes advantageous to employ an inert liquidnon-aqueous reaction medium such as paraffin hydrocarbons, benzene,toluene, xylene, dioxane, acetone, dimethyl formamide, tetrahydrofuranand the like and after polymerization removing the medium such as bydistillation and/or decantation in order to recover the polymer.

Synthetic polymeric materials, i.e., those high molecular weight organicmaterials which are not found in nature, with which the ethanediphosphonates are advantageously employed may be either linear orcross-linked polymers and they may be either those which are produced byaddition polymerization or by condensation.

An important class of polymers which are beneficially modified accordingto the invention are those obtained from a polymerizable monomercompound having ethylenic unsaturation.

A particularly preferred class of polymers flame-proofed hereby consistsof the polymerized vinyl and vinylidene compounds, i.e., those havingthe radical. Compounds having such a radical are, e.g., the solidpolymeric alkenes, such as polyethylene, polypropylene, polyisobutyleneor ethylene propylene copolymer; polymerized acrylyl and alkacrylylcompounds such as acrylic, chloroacrylic and methacrylic acids,anhydrides, esters, nitriles and amindes, for example, acrylonitrile,ethyl or butyl acrylate, methyl or ethyl methacrylate, methoxymethyl or2- (2-butoxyethoxy)ethyl methacrylate, Z-(cyano-ethoxy) ethyl3-(3-cyanopropoxy)propyl acrylate or methacrylate, 2-(diethylamino)ethyl or 2-chloroethyl acrylate or methacrylate, acrylicanhydride or methacrylic anhydride; methacrylamide or chloroacrylamide,ethyl or butyl chloroacrylate; the olefinic aldehydes such as acrolein,methacrolein and their acetals; the vinyl and vinylidene halides such asvinyl chloride, vinyl fluoride, vinylidene fluoride andl-chloro-lfluorethylene; polyvinyl alcohol; the vinyl carboxylates suchas vinyl acetate, vinyl chloroacetate, vinyl propionate, and vinyl2-ethyl-hexanoate; the N-vinyl imides such as N-vinylphthalimide andN-vinyl-succinimide; the N-vinyllactams such as N-vinylcaprolactam andN-vinylbutyrolactam; the vinyl aromatic hydrocarbon compounds such asstyrene, amethylstyrene, 2,4-dichlorostyrene, aor ,B-vinylnaphthalene,divinylbenzene and vinylfiuorene; the vinyl ethers such as ethyl vinylether or isobutyl vinyl ether; vinyl-substituted heterocyclic compoundssuch as vinylpyridine, vinylpyrrolidone, vinylfuran or vinylthiophene;the vinyl or vinylidene ketones such as methyl vinyl ketone orisopropenyl ethyl ketone; vinylidene cyanide; etc. Homopolymers of theabove compounds or copolymers or terpolymers thereof are beneficiallymodified by the ethane diphosphonates. Examples of such copolymers orterpolymers are those obtained by polymerization of the followingmonomer mixtures: vinyl chlorine vinyl acetate, acrylonitrilevinylpyridine, styrene methyl methacrylate; styrene N-vinylpyrrolidone,cyclohexyl methacrylate vinyl chloroacetate, acrylonitrile vinylidenecyanide, methyl methacrylate vinyl acetate, ethyi acrylatemethacrylamide ethyl chloroacrylate, vinyl chloride vinylidene chloridevinyl acetate, etc.

Other presently employed polymers of compounds having the ethylenicgroup,

are homopolymers, copolymers and terpolymers of the a, tiolefinicdicarboxylic acids and the derivatives thereof such as the anhydrides,esters, amides, nitriles and imides, e.g., methyl, butyl, Z-ethylhexylor dodecyl fumarate or maleate, maleic, chloromaleic, citraconic oritaconic anhydride, fumaronitrile, dichlorofumaronitrile orcitracononitrile, fumaramide, or maleamide; maleimide orN-phenylmaleimide, etc. Examples of particularly useful copolymers andterpolymers prepared from the a, ,B-olefinic dicarboxy compounds are thecopolymers of maleic anhydride and a vinyl compound such as ethylene,propylene, isobutylene, styrene, a-methylstyrene, vinyl acetate, vinylpropionate, methyl isopropenyl ketone, isobutyl vinyl ether, etc., thecopolymers of dialkyl fumarate such as ethyl or butyl fumarate and avinyl compound such as styrene, vinyl acetate, vinylidene chloride,ethyl methacrylate, acrylonitrile, etc.

Readily and advantageously modified by the present ethane diphosphonatesare also the polymers and copolymers of unsaturated, cyclic esters ofcarbonic acid, e.g., homopolymeric vinylene carbonate or the copolymersof vinylene carbonate with ethylenic compounds such as ethylene, vinylchloride, vinyl acetate, 1,3-butadiene, acrylonitrile,methacrylonitrile, or the esters of methacrylic or acrylic acid.

Readily and advantageously modified by the present ethane diphosphonatesare also the polyarylcarbonate polymers such as the linearpolyarylcarbonates formed from diphenols or dihydroxy aromatic compoundsincluding single and fusedring nuclei with two hydroxy groups as well asmonohydroxysubstituted aromatic residues joined in pairs by variousconnectin g linkages. Examples of the foregoing include dihydroxybenzenes, naphthalenes and the like, the dihydroxydiphenyl ethers,sulfones, alkanes [bis(4-hydroxyphenyl)2.2-propane], ketones and thelike.

Advantageously modified by the present ethane diphosphonates are alsopolymers, copolymers or terpolymers or polymerizable compounds having aplurality of double bonds, e.g., a rubbery, conjugated dienepolymerizate such as homopolymerized 2,3-butadiene, 2-chl0robutadiene orisoprene and linear copolymers or terpolymers such as butadieneacrylonitrile copolymer, isobutylene butadiene copolymer (butyl rubber)butadiene styrene copolymer of 2- chloro-butadiene vinylidene cyanideacrylonitrile terpolymer; esters of saturated dior polyhydroxy compoundswith olefinic carboxylic acids such as ethylene glycol dimethacrylate,triethylene glycol dicrotonate or glyceryl triacrylate; esters ofolefinic alcohols with dicarboxylic acids or with olefinicmonocarboxylic acids such as diallyl adipate, divinyl succinate, diallylfumarate, allyl methacrylate or crotyl acrylate and otherdiethylenically unsaturated compounds such as diallyl carbonate, divinylether or divinylbenzene, as well as the cross-linked polymeric materialssuch as methyl methacrylate diallyl methacrylate copolymer or butadienestyrene divinyl-benzene terpolymer.

Polymerized materials prepared by subsequent reaction of the preformedvinyl polymers, e.g., polyvinyl alcohol, the polyvinyl acetals such aspolyvinyl formal or polyvinyl butyral, or completely or partiallyhydrolyzed polyacrylonitrile are likewise modified in properties by thepresent ethane diphosphonates to give polymeric materials of enhancedutility.

Polymeric materials with which the present ethane diphosphonates can beemployed as adjuvants are also polymers which contain elements such assulfur, phosphorus, boron or silicon, e. g., the sulfides, sulfones,sulfoxides, sulfites, sulfates and sulfonates such as the polymers andcopolymers of vinyl sulfide, vinyl sulfone, Z-propenyl sulfoxide,ethylene sulfonic acid and its salts, esters and amides, and sulfonatedpolystyrene; the olefin sulfur dioxide polymers, the phosphines,phosphites, phosphates and phosphonates such as diphenylvinylphosphine,allyl phosphite and methallyl phosphite, ethylene phosphonic acid andstyrenephosphonic acids and their salts, esters and amides; the silanessuch as dimethylvinylsilane, diphenylvinylsilane andmethylphenylvinylsilane, etc.

A class of synthetic polymeric materials with which the present ethanediphosphonates are very useful comprises the cellulose derivatives,e.g., the cellulose esters such as cellulose acetate, cellulosetriacetate, or cellulose acetate butyrate, the cellulose ethers such asmethyl or ethyl cellulose, cellulose nitrate, carboxymethyl cellulose,cellophane, rayon, regenerated rayon, etc. The ethane diphosphonates maybe incorporated into films of such cellulose derivatives by adding themto the solutions from which the films are cast or into the melts fromwhich the fibers are extruded.

The present ethane diphosphonates are particularly suited to themodification of liquid resin compositions of the polyester type, e.g.,the linear polyesters which are obtained by the reaction of one or morepolyhydric alcohols with one or more a, B-unsaturated polycarboxylicacids alone or in combination with one or more saturated polycarboxylicacid compounds, or the cross-linked polyester resins which are obtainedby reacting the linear polyester with a compound contaming a oHi=cgroup.

The cross-linking component of the presently modified polyester resinmay be, e.g., styrene, the nuclear or sidechained substituted styrenessuch as 3,4-dicholrostyrene, achloro-styrene, a-methylstyrene; othervinyl-substituted hydrocarbons such as aor B-vinylnaphthalene or4-vinylbiphenyl; the olefinic carboxylic acids and the esters, nitriles,

amides and anhydrides thereof such as acrylic acid, methacrylic acid,ethyl acrylate, or acrylonitrile; the vinyl esters such as vinyl acetateor vinyl chloroacetate; the olefinic ketones such as ethyl vinyl ketoneand isopropenyl methyl ketones; the alkenes such as isobutylene and2-pentene; the olefinic ethers such as vinyl ethyl ether and vinylisobutyl ether; etc.

The epoxy resins are another class of polymeric materials with which thepresent ethane diphosphonates are compatible and are advantageouslyused. These resins are condensation products formed by the reaction of apolyhydroxy compound and epichlorohydrin, which condensation productsare subsequently cured by addition of cross-linking agents. The hydroxycompound may be e.g., ethylene glycol, 4,4- isopropylidenediphenol, etc.The cross-linking agent employed in the curing or hardening step may bea dicarboxylic compound such as phthalic anhydride or adipic acid, butis more generally a polyamine such as ethylene diamine, mor pphenylenediamine or diethylenetriamine.

The polyurethanes comprise another class of polymeric materials whichare beneficially modified by the present ethane diphosphonates. Thepolyurethanes, like the abovementioned polyesters, are commercialmaterials which are employed in structural applications, e.g., asinsulating foams, in the manufacture of textile fibers, as resin basesin the manufacture of curable coating compositions and as impregnatingadhesives in the fabrication of laminates of woods and other fibrousmaterials. Essentially the polyurethanes are condensation products of adiisocyanate and a compound having a molecular weight of at least 500and preferably about l,500-5,000, and at least two reactive hydrogenatoms, i.e., hydrogen atoms determinable by the Zerewitinoff method. Theuseful active-hydrogen containing compounds may be polyesters preparedfrom polycarboxylic acids and polyhydric alcohols, polyhydricpolyalkylene ethers having at least 2 hydroxy groups, polythioetherglycols, polyesteramides, etc.

The polyesters or polyesteramides used for the production of thepolyurethane may be branched and/or linear, e.g., the esters of adipic,sebacic, 6aminocaproic, phthalic, isophthalic, terephthalic, oxalic,malonic, succinic, maleic, cyclohexanel,2-dicarboxylic,cyclohexane-l,4-dicarboxylic, polyacrylic, naphthalene-l,Z-dicarboxylic,fumaric, itaconic, etc., with polyalcohols such as ethylene glycol,diethylene glycol, pentaglycol, glycerol, sorbitol, triethanolamine,di(B-hydrox yethyl)ether, etc. and/or amino alcohols such asethanolamine, 3-aminopropanol, 4-aminopropanol, 5-

aminopentanol -l, 6-aminohexanol, lO-aminodecanol, 6-amino-S-methylhexanoll p-hydroxymethylbenzylamine, etc,; and withmixtures of the above polyalcohols and amines, ethylene diamine,hexamethylene diamine, 3-methylhexamethylene diamine, decamethylenediamine and m-phenylenediamine, etc. and/or amino-alcohols, etc. In theesterification, the acid per se may be used for condensation or, wheredesirable, equivalent components such as the acid halide or anhydridemay be used.

The alkylene glycols and polyoxyalkylene or polythioalkylene glycolsused for the production of the polyurethanes may comprise ethyleneglycol, propylene glycol, butylene glycol -2,3, butyleneglycol-l,3,2-methylpentanediol-2,4,2- ethylhexane-diol-l,3,hexamethylene glycol, styrene glycol and decamethylene glycol, etc., anddiethylene glycol, triethylene glycol, tetraethylene glycol,polythioethylene glycol, polyethylene glycols 200, 400 and 600 etc.,dipropylene glycol, tripropylene glycol, trithiopropylene glycol,polypropylene glycols 400, 750, 1,200 and 2,000 etc.

Broadly, any of the polyesters, polyisocyanate-modified polyesters,polyesteramides, polyisocyanate-modified polyester-amides, alkyleneglycols, polyisocyanate-modified alkylene glycols, polyoxyalkyleneglycols and polyisocyanatemodified polyoxyalkylene glycols, etc. havingfree reactive hydrogen atoms, free reactive carboxylic and/or especiallyhydroxyl groups may be employed for the production of the polyurethanes.Moreover, any organic compound containing at least two radicals selectedfrom the class consisting of hydroxyl and carboxyl groups may beemployed.

The organic polyisocyanates useful for the production of thepolyurethanes include ethylene diisocyanate, ethylidene diisocyanate,propylene-l ,Z-diisocyanate, butylene-l ,3-diisocyanate, hexylenel,6diisocyanate, cyclohexylenel ,Z-diisocyanate, m-phenylenediisocyanate, 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate,3,3'-dimethyl-4,4'- biphenylene diisocyanate,3,3-dimethoxy-4,4-biphenylene diisocyanate,3,3'-diphenyl-4,4-biphenylene diisocyanate, 3,3-dichloro-4,4-biphenylenediisocyanate, triphenylmethane triisocyanate, 1,5-naphthalenediisocyanate or polyisocyanates in a blocked or inactive form such asthe bisphenyl carbamates of toluylene diisocyanate, p, p-diphenylmethanediisocyanate, p-phenylene diisocyanate and 1,5- naphthalenediisocyanate, etc.

For preparation of the flameretardant polyurethanes, the present ethanediphosphonates are preferably added to a mixture of the reactants andcatalyst before hardening. The hardened molded pieces or foams arerendered flame-retardant by the inclusion therein of the ethanediphosphonates in quantities of from about 2 percent to about 25 percentby weight of the polyurethane. Use of the present ethane diphosphonatesin the polyurethane foams can also, in some applications, improve themechanical properties of the foams,

Phenolic resins are also beneficially modified by the present ethanediphosphonates, which compounds can be incorporated into the resineither by milling in molding applications or by addition to film-formingor impregnating and bonding solutions previous to casting. Phenolicresins with which the present ethane diphosphonates compounds areemployed are, for example, the phenolaldehyde resins prepared fromphenols such as phenol, cresol, xylenol, resorcinol, 4-butylphenol,4-phenylphenol, and aldehydes such as formaldehyde, acetaldehyde, orbutylraldehyde in the presence of either acidic or basic catalysts,depending upon whether the resin is intended for use as a molding orextruding resin or as the resin base in coating and impregnatingcompositions.

The aminoplasts comprise another group of aldehyde resins which arebeneficially modified by the present ethane diphosphonates. Examplesthereof are the heat-convertible condensation products of an aldehydewith urea, thiourea, guanidine, cyanimide, dicyandiamide, alkyl or arylguanamines, and the triazines such as melamine, 2-chloro-4,6- diamino-l,3,5-triazine and 2-hydroxy-4,6-diamino-1,3,5- triazines. The presentadjuvants are compatible with the aminoplasts; and depending upon thequantity of ethane diphosphonates used, they serve to modify theirphysical properties as well as to render them fire-retardant. When theaminoplasts are destined for use as impregnating agents, bondingadhesives, coatings and casting of films, the ethane diphosphonates areincorporated into solutions or suspensions in which the aminoplast iscarried. The resulting mixtures give strong, fire-retardant laminateswhen sheets of paper, glass, cloth or fabric are impregnated therewithand cured.

Also beneficially modified by the present ethane diphosphonates are thenylons, i.e., the superpolyamides which are generally obtained by thecondensation of a diamine, e.g., hexamethylenediamine with adicarboxylic acid, e.g., adipic acid. Depending upon the quantity ofethane diphosphonates employed and the individual nature of thecompound, there are obtained flame-retardant and/or dye receptoreffects.

Other polyamides with which the present ethane diphosphonates arebeneficially employed, e.g., for improvement in reduced burning rates,are the polypeptides which may be prepared, e. g., by reaction ofN-carbobenzyl oxyglycin with glycine or a mixture of glycine and lysine,or an N-carboxy amino acid anhydride such as N-carboxyDL-phenylalanineanhydride; the polymeric lactams, e.g,, polycaprolactam, piperidone,2-oxohexamethyleneimine and other cyclic amides. The present ethanediphosphonates can be incorporated into molding or extrudingcompositions for flame-recompositions.

The present ethane diphosphonates are also advantageously employed asadjuvants for polymeric aldehydes, e.g., homopolymeric, high-molecularweight formaldehyde.

The present phosphonic anhydrides are also adjuvants for linear polymersobtained by the self-condensation of bifunctional compounds generally,e.g., the polyethers which are derived by the self-condensation ofdihydric alcohols such as ethylene glycol, propylene glycol orhexamethylene glycol; the polyesters which are obtained by theself-condensation of hydroxy acids such as lactic acid or4-hydroxybutyric acid, the polyamides which are prepared by theself-condensation of amino carboxylic acids such as 4-aminobutyric acidor 6- aminocaproic acid; the polyanhydrides which are formed by theself-condensation of dicarboxylic acids such as sebacic acid 'or adipicacid, etc. The present ethane diphosphonates are flame retardants forsuch self-condensation products, generally; and where transparentizingeffect and dye receptivity are lacking, the ethane diphosphonates areoften instrumental in ameliorating such deficiencies.

The following examples are presented to illustrate the invention, withparts and percentages by weight being used in the examples unlessotherwise indicated. All polymeric compositions illustrated in thefollowing examples will exhibit reduced burning rates and can beclassified as either nonburning or self-extinguishing.

. EXAMPLE I A copolymeric composition is obtained by heating about 0.15mols of ethylene diamine and about 0.4 mols of the above describedcompound No. l, i.e., H C(OH )C(H)( P0 149 in benzene to about 80 C. forabout 4% hours. The reaction batch is cooled to room temperature and thebenzene distilled off yielding a polymeric composition which softens atabout 25 l-284 C.

EXAMPLE ll A copolymeric composition is also obtained by blending about0.3 mols of hexamethylene diamine and about 0.1 mol of an indicatedethane diphosphonate compound, and heating the mixture for 5 hours atabout 164 C. and thereafter cooling to room temperature. The addedcompounds are those heretofore described as compound Nos. 2, 7, l3 and24.

EXAMPLE III A copolymeric composition is also obtained by blending about0.3 mols of ethylene glycol and about 0.1 mol of an indicated ethanediphosphonate compound and then heating the mixture at'90" C. for aboutlhour. Upon cooling to room temperature the composition sets to a solidpolymeric composition. The added ethane diphosphonate compounds arethose heretofore described as compound Nos. 1, l0, l6, 17, 22 and 29.

EXAMPLE iv EXAMPLE V v A polymeric composition is obtained by blending46 parts of oleic acid, 22 parts of glyeerine, 18 parts of an indicatedethane diphosphonate compound, and a trace of toluene sulfonic acidandheating the mixture to about 149 C. under a flowing nitrogen blanketsufficient to exclude air and to remove by-product waterv After about 61minutes gelatin occurs and the batch is cooled to room temperature toyield a solid polymeric composition. The added phosphonic anhydridecompounds are those heretofore described as compound Nos. 4 5, 8, 21 and27.

EXAMPLE VI This example illustrates the preparation of a rigidpolyurethane foam using one of the indicated ethane diphosphonatestherein as the flame retardant.

3. Polyisocyanate Mondur MR" a polymethylene polyphenylisocyanate havingan available NCO content of about 32% and a viscosity at 25' C. of200250 cps.

For the above formulation, all of the components except thepolyisocyanate are blended to a homogeneous mixture, and then thepolyisocyanate is added, 1 the mixture blended thoroughly, and then isallowed to polymerize and rise.

EXAMPLE Vll A composition is also obtained by adding one of theindicated ethane diphosphonate compounds in an amount suffcient to beabout 10 percent by weight based onthe weight of the total solidscontent of a 10 percent benzene solution of a 72:28 molar ratiostyrene-acrylonitrile copolymer. The benzene is distilled off yielding apolymeric composition. The added ethane diphosphonate compounds arethose heretofore described as Nos. 2, 9, l5, 17, 20 and 28.

EXAMPLE Vlll To a polymer blend of an unsaturated polyester prepared bycondensing one mol of an indicated ethane diphosphonate, a mol of maleicanhydride, 1% mol of phthalic anhydride and 2.1 mols of propylene glycolto an acid number of about 40 at 200 C., cooling the mixture anddissolving the mixture in a sufficient amount of styrene monomer so thatthe resulting mixture comprises 30 parts of styrene monomer to 70 partsof polyester, there is added a small amount (3 percent w./w.) of

benzoyl peroxide and the resulting mixture is polymerizedat C. yieldinga thermosetting resin. The added ethane diphosphonate compounds arethose heretofore described as compound Nos. 1, 5, 6, 10, 17, 27 and 30.

EXAMPLE IX To a granular blend of a polystyrene and butadiene-styrenecopolymer containing about 6 percent by weight of the copolymer there isadded one of the indicated ethane diphosphonate compounds in an amountof about 4 percent by weight by blending for 15 minutes in a tumblingtype laboratory blender and then extruding the blend into rods. Theadded ethane diphosphonate compounds are those heretofore described ascompounds Nos. 4, 7, ll, l3, l4, 19, 24 and 26.

EXAMPLE X To melted samples of a natural high molecular weight lowdensity polyethylene having a density of about 0.9, a melt index ofabout 0.3 grn./l0 min., a softening temperature of about C., and atensile strength (ultimate) of-2,300 psig, various amounts of one of theindicated ethane diphosphonates sufficient to make compositions whereinthe added ethane diphosphonate comprises from about 4 to 8 percent ofthe total weight of the composition are added. The samples are cooled toroom temperature to provide polymer compositions. The added ethanediphosphonate compounds are those heretofore described as compound Nos.2, 4, 5, 8 20, 27 and 29.

EXAMPLE XI EXAMPLE XII Improved films are also obtained when one of theindicated ethane diphosphonate compounds is added to a 10 percentsolution of a 50:50 molar ratio styrene-methyl methacrylate copolymer inbenzene in an amount sufficient to be about 30 percent by weight of thetotal solids content and then cast into films which are flexible. Theadded ethane diphosphonate compounds are those heretofore described ascompound Nos. 2, 7, 13, 20, 24 and 29.

EXAMPLE XIII With about 3 parts of a commercially available condensationproduct oflinoleic acid and a polyamine having an amine value of from290-320 and a viscosity of 80-120 poises at 40 C., there is mixed 7parts of diglycidyl ether of Bis-phenol A and a sufficient amount of oneof the indicated ethane diphosphonates to make a composition havingabout 16 percent by weight. based on the weight of the totalcomposition, of the ethane diphosphonate. The resulting reaction mixtureis poured into a small aluminum pan coated with a silicone grease toprevent sticking) and heated in an oven at 100 C. for about 2 hours.After cooling to room temperature an epoxy resinous product is obtained.The added ethane diphosphonate compounds are those heretofore describedas compound Nos. 4, 7,11,13,14,]9, 24 and 26.

EXAMPLE XIV To samples of a commercial cellulose acetate butyrate havingan average acyl content of 13 percent and 37 percent butyryl and aviscosity range of 17-33 seconds (64-124 poises) as determined by ASTMmethod D-l343-54T (which is incorporated herein by reference) in thesolution described as Formula A, ASTM method D-871-54T (which isincorporated herein by reference) are blended on hot mill rolls asufficient amount of one of the indicated ethane diphosphonates suchthat the final compositions contain from about 10 to percent by weightof the added ethane diphosphonate. After blending the samples are cooledto room temperature to obtain a polymeric composition. The added ethanediphosphonates are those heretofore described as compound Nos. l, 5, 6,9,10,15,17, 27 and 30.

EXAMPLE XV To a 10 percent ethylene dichloride solution of polyvinylacetate there is added one of the indicated ethane diphosphonatecompounds in a quantity which is one-half by weight to that of thepolyvinyl acetate present in the solution. Films cast from the resultingmixture are flexible. The added ethane diphosphonate compounds are thoseheretofore described as compound Nos. 5, 8, ll, 12 and 22.

EXAMPLE XVI To melted samples of a commercial rigid polymethylmethacrylate polymer there is blended on hot mill rolls one of theindicated ethane diphosphonate in an amount sufficient to provide about20 percent of the ethane diphosphonate per total weight of thecomposition. The samples are milled into sheets in order to obtainpolymeric compositions. The added ethane diphosphonates are thoseheretofore described as compound Nos. 2, 9, 15, 17 and 20.

EXAMPLE XVII To parts ofa polyvinyl chloride resin there is added 50parts of dioctyl phthalate and 50 parts of H C(OH)C(OH)[ PO (C H Themixture is placed on hot mill rolls and blended. When thoroughlyblended, the product is stripped from the rolls and pressed into squareshaped pieces which are soft pliable plastic.

EXAMPLE XVIII A salt is prepared from hexamethylene diamine and adipicacid by mixing about 144 parts of amine with about parts of the acid inthe presence of 1,300 parts of 95 percent ethyl alcohol and 210 parts ofwater. The mass is warmed until complete solution occurs and then cooledto obtain crystals of hexamethylene diammonium adipate. To this salt isadded about 16 parts of H C(OI-I)C(OI-I)[PO (C I-I,,) and the mixtureheated for about 3 hours with an equal weight of mixed xylenols (B.P.218-222 C.) and the entire reaction mass is then poured gradually withstirring into a large volume of ethyl alcohol. The modified polyamideprecipitates as a granular powder and is filtered, washed with alcoholand dried.

EXAMPLE XIX The various organic compositions prepared in the aforegoingExamples I through XVIII and which contain the ethane diphosphonates areeach individually subjected to the burn test, ASTM-Dl692-59T, heretoforedescribed. In all cases, the organic compositions are found to eitherdemonstrate no evidence of burning or to be self-extinguishing. The sameorganic compositions which do not contain the ethane diphosphonates areutilized as the control materials and are tested in the same manner.These control materials are found in all cases to either burn or gobeyond the second gauge line, i.e., they do not exhibitself-extinguishing" characteristics as defined by said test. Thus theutility of the present invention compositions is vividly demonstrated.

EXAMPLE XX A control polyurethane foam is prepared by heating 10 mols oftrimethylolpropane with 6 mols of adipic acid to an almost nil acidnumber and a hydroxyl number of 504. This polyester is formed with itsown prepolymer, the prepolymer being a mixture of 20% of the abovepolyester and 80 percent of toluene diisocyanate. The mixture of theabove two formulations is expanded with trichlorofluoromethane in thenormal manner to yield a 2.5 pounds per cubic foot density foam. Thefire resistance of this foam, measured by the American Society forTesting Materials D-75 7 Test (which is incorporated herein byreference), is found to be about 10 inches per minute.

The polyurethane foam formulation described immediately above is againprepared; however, 7.5 percent by weight of an ethane diphosphonatehaving the formula H C(OH)C(OI-I)[ PO (C II is added. The fireresistance of the final urethane foam is measured by the ASTM D-757 testindicated above. The results of this test show the fire resistance ofthe foam is less than about 0.6 inches per minute.

What is claimed is:

l. A flame resistant polyurethane prepared by reacting 1 a polyol, (2)an organic polyisocyanate and (3) from about 1 percent to about 50percent by weight, based on the total weight of l) and (2), of an ethanediphosphonate having the formula wherein R is selected from the groupconsisting of hydrogen, alkyl containing from one to four carbon atomsand mixtures thereof.

2. A flame resistant polyurethane prepared by reacting l) a polyol, (2)an organic polyisocyanate and (3) from about 1 percent to about 50percent by weight, based on the total weight of I) and (2), of an ethanediphosphonate having the formula wherein R, is selected from the groupconsisting of hydrogen, alkyl containing from one to four carbon atomsand mixtures thereof, and R is an alkyl group containing from one tofour carbon atoms.

3. A flame resistant polyurethane prepared by reacting l a polyol (2) anorganic polyisocyanate and (3) from about 1 percent to about 50 percentby weight, based on the total weight of( l and (2), of an ethanediphosphonate having the formula

2. A flame resistant polyurethane prepared by reacting (1) a polyol, (2)an organic polyisocyanate and (3) from about 1 percent to about 50percent by weight, based on the total weight of (1) and (2), of anethane diphosphonate having the formula
 3. A flame resistantpolyurethane prepared by reacting (1) a polyol (2) an organicpolyisocyanate and (3) from about 1 percent to about 50 percent byweight, based on the total weight of (1) and (2), of an ethanediphosphonate having the formula
 4. A flame resistant polyurethaneprepared by reacting (1) a polyol, (2) an organic polyisocyanate and (3)from about 1 percent to about 50 percent by weight, based on the totalweight of (1) and (2), of an ethane diphosphonate selected from thegroup consisting of 1,2-dihydroxyethane-1,1-diphosphonic acid,2-cyano-1-hydroxyethane-1,1-diphosphonic acid,diphenyl-2-benzoyl-1-hydroxyethane-1,1-diphosphonate,2-thiomethyl-1-hydroxyethane-1,1-diphosphonic acid,2-oxyethane-1,1-diphosphonic acid, and mixtures thereof.